Sighting apparatus for ascertaining the velocity and direction of movement of aerial targets



235% 1 3 5R Mi SEARCH ROOM v r 1 MW I NWW W y 49- A. L. RICORDEL 2,476,625 SIGHTING APPARATUS FOR ASCERTAINING THE VELOCITY ARD DIRECTION OF MOVEMENT OF AERIAL TARGETS Filed Nov. l7, 1954 6 Sheets-Sheet 1 l I l AUGUSTC LOUIS RKZORDEL BS OMMJJNM/ hz'sattorney SEARCH R05 July 19, 1949. A. 1.. RICORDEL 2,476,625 SIGHTING APPARATUS FOR ASCERTAINING THE VELOCITY AND DIRECTION OF MOVEMENT OF AERIAL TARGETS Filed Nov. 17, 1934 6 Sheets-Sheet 2 E2 EVA 7/0 MINT/#6 Ill/61 VAL UE 0F V e M m 0 W 7 w u F m M MM Mm 5 U 0 M a A M U T F ON "a J8 I I0 5 0 a I H 1 2 7 AL 7/71/05 A 7w:- sou:

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SIGHTING APPARATUS FOR ASCERTAINING THE VELOCITY AND DIRECTION OF MOVEMENT 0F AERIAL TARGETS Filed Nov. 17, 1934, 6 Sheets-Sheet 3 Auausrs LOUIS RICORDEL a bisfiltorne y SEARCH RQQR July 19, 1949. A. L. RICORDEL 2,476,625

SIGBTING APPARATUS FOR ASCERTAINING THE VELOCITY AND DIRECTION OF MOVEMENT OF AERIAL TARGETS Filed Nov. 17, 1934 6 Shets-Sheet 4 C V 3 z! a vbr B 2 l x v 19 I I 0 I 3 x: p

lNVE/VTOH: AUGUSTE LOUIS R\CORDEL & mew/1M his attorney SEWER RGO? y 19, 1949- A. L. RICORDEL SIGHTING APPARATUS FOR ASCERTAINING THE VELOCITY AND DIRECTION OF MOVEMENT OF AERIAL TARGETS 6 Sheets-Sheet 5 Filed NOV- 17. 1934 AUGUSTE LOUIS RICORDEL 0 claw/{M Jul: 61 [for/v e51 Patented July 19, 1949 $EARCi-i tit SIGHTING APPARATUS FOR ASCERTAINING THE VELOCITY AND DIRECTION OF MOVE- MENT OF AERIAL TARGETS Auguste Louis Ricordel, Paris, France, assignor to the society said La Precision Moderne, Paris, France, a body corporate of France Application November 17, 1934, Serial No. 753,547 In France November 18, 1933 Section 3, Public Law 690, August 8, 1946 Patent expires November 18, 1953 Claims.

The invention relates to an auxiliary pointing apparatus by means of which the speed and direction of movement of a moving target may be determined and which is particularly applicable to anti-aircraft firing.

It is known that in anti-aircraft firing three elements are needed for effecting the corrections as to altitude and horizontal displacement of the target; these three elements are the range, the speed, and the direction of movement of the target. The first of these elements is ascertained with precision by telemetric measuring, but the speed is generally merely estimated according to the type of the aircraft and the direction of movement is assumed by guess-work of the gunner Which results in considerable error. In other cases, the values of the speed and direction of movement of the aircraft are ascertained by a number of observations and calculations which consume a fairly considerable time. This is a great drawback, particularly in cases when the aircraft changes its direction frequently in order to avoid being hit by anti-aircraft artillery projectiles.

The present invention has for its object an apparatus adapted to eliminate these drawbacks and to make available at any moment and continuously precise data on the speed and direction of movement of the target; this apparatus is characterized by the feature that it comprises an orientable friction roller in constant contact with a bearing surface, means for displacing this roller relatively to the bearing surface in two, mutually normal directions, at velocities proportional to the horizontal components of the speed of the target in the plane of sighting (radial-horizontal component) and in a plane vertical thereto (lateral component), respectively, and means for deriving the values of said components from the displacements, in elevation and in azimuth, of the sighting device of the apparatus.

Two forms of embodiment of the apparatus constructed according to the invention are hereinafter described by way of example and illustrated in the accompanying drawing, in which:

Figs. 1 to 3 are diagrams illustrating the principles on which the apparatus is based.

Fig. 4 is a diagrammatic view of a first embodiment of the invention in which the orientable roller is mounted on a stationary pivot and rests on the surface of a rotating sphere.

Fig. 5 shows diagrammatically a device for determining the value of the horizontal range of the target on the basis of its telemetric range.

Fig. 6 is an elevational section of a modified em- 2 bodiment of the apparatus shown in Fig. 4 equipped with the device shown in Fig. 5.

Figs. 7 and 8 are diagrams illustrating another manner of resolving the speed vectors for obtaining the horizontal range of a target on the basis of its telemetric range.

Figs. 9 and 10 are diagrams illustrating the resolution of the speed vectors taking into account the variations of altitude of the target.

Fig. 11 shows a modification incorporating a device such as shown in Figs. 9 and 10.

Let 0 (Fig. 1) be the location of the gun A0 the position of the target at a given moment; it will be supposed that the target remains at a constant altitude during the time of sighting, so that its speed may be represented by a vector AnA in a horizontal plane P which is at a distance AoA'o=I-I from the horizontal plane P passing through the point 0. The vector AoA may be resolved into two vectors one of which, AOB=VhT, is in the plane of sighting AoOA'o, and the other, AB=Vz., in a plane normal to that plane and lying in the P plane. The projection of these two vectors onto the horizontal plane P are shown at Ao'B' and at AB, and it will be seen that the radial-horizontal component, AoB=A'oB', is equal to the rate of change of the horizontal distance 0A'0=Dh of the target, whereas the lateral component, AB=A'B, is equal to the product of that horizontal distance and the angular velocity in azimuth AoOA'=W of the target. It is suflicient, therefore, in order to obtain these two components, to know at any moment the horizontal distance Dh=0Au (the radial speed .AoB, or A'oB, is the variation of D11 during the unit of time), which is easily derived from the angle of altitude AOOA0=S and from the altitude AoA'o=H or from the telemetric distance OA0=D0, whilst the lateral component V1. is derived from the horizontal range and from the angular azimuth displacement We. The desired value AoA of the speed of the target is obtained by combining the vectors A013 and AB.

The recomposing of the vectors Vhr and VL is effected according to this invention, by means of a device operating on the principle illustrated in Figs. 2 and 3. This device comprises a roller l mounted in a fork shaped member 2 pivoted on a pin carried by a supporting member 3 in respect to which said roller I has an eccentric position. The roller I rests on a bearing 5. When the supporting member 3 is displaced in respect to the fixed bearing surface 5 simultaneously in two directions at right angles to each other at velocities proportional to vhr and to VL, respectively, the roller is set according to the direction of the resultant of these two vectors, so that a hand 6 integral with the fork shaped member 2 and moving over a graduated dial 1 integral with the supporting member 3, indicates the an gle made by the direction of movement of the aircraft with the plane of sight AoOAo. It is understood that instead of pivoting the roller i on a supporting member movable in respect to a fixed bearing surface, the pivoting axis 4 may be fixed and the bearing surface may be displaced in two directions at right angles to each other. Thus, in Figure 3, this movable bearing surface 5 is constituted by a sphere (supported by a ball or a disk) driven in rotation by two driving rollers 8 and 9 contacting with a horizontal great circle of said sphere and set at 90 from each other and rotating at velocities respectively proportional to Va: and to V1,, Whereas the receiving train is constituted by two rollers l, I mounted on a supporting member ID pivoted around an axis in line with the vertical diameter 4 of the sphere. Such a disposition has the advantage of permitting the use of greater velocities for driving the recomposing device and thus to eliminate the influence of inertia on the receiving train.

Fig. 4 is a plan view of the apparatus of which the principle has been diagrammatically illustrated in Figs. 1 to 3.

This apparatus comprises an assembly which may be rotated in azimuth and which forms a device providing a value proportional to the horizontal distance of the target, said device comprising an altitude setting screw I5 along which a nut 28 may be moved without rotation, a horizontal screw [3 along which a nut may be similarly moved without rotation, an elevation pointing wheel [9 driving the screw l8 and a sighting tube 24 fixed on the rod 23 articulated on one hand at 25 on the nut 20 and sliding, on the other hand, in a socket 26 articulated at 21 on the nut 28 movable along the altitude screw I5.

When the altitude pointing wheel I9 is rotated so as to point the sighting tube upon the target, the distance between the axes 25 and 21, measured along the rod 23, is proportional to the range OA0=D0 (Fig. 1) of the target, whilst the distance between 25 and 21 measured in horizontal projection along the horizontal screw 18 is proportional to the horizontal range Dn=OA'o. The variations of the horizontal distance between 25 and 2'1, i. e. the speed of the displacement of the nut 20 pro duced during sighting by the altitude pointing wheel Is, as well as the speed of rotation of the screw I8, is thus proportional to the radial-horizontal component Vhr of the movement of the target.

The determination of the lateral component AB=WaDh of the speed of the target is performed by means of the following members: an azimuth pointing wheel 32 driving in azimuthal rotation the rotatable device also drives by means of shaft 39 a small pinion 40 meshing with a vertical toothed plate 4|, the shaft 42 of which is in the vertical plane ,of the axis 21. The angular displacements of this plate 4| are proportional to the variations of the azimuth of the target, i. e. to Wa; for obtaining the product WaDh the nut 20 moving on the screw l8 driven by the altitude Wheel 19 carries a vertical roller 43 by means of a supporting member 44, said roller being in contact with the plate 4|. The distance from the point of contact of the roller 43 with the plate it to the centre of the latter being proportional to D11, it is clear that the number of revolutions performed by the roller 43 is proportional to WaDh. This roller 43 is slidably keyed on a shaft 45 which drives, together with the shaft 18 controlled by the elevation wheel [9, the device for reconstructing the resultant speed vector. This device comprises a sphere 46 which is supported from below by a suitable supporting member such as a screw or a roller, on which it may freely rotate, and which is driven by two pairs of driving rollers 4'l41, 4843, whilst the orientable receiving train is constituted by two rollers 22'-22 pivoted around an axis in line with the vertical diameter 49 of the sphere 46.

The rollers 41-41 are placed in a plane parallel to the plane of sight and the rollers 48-48 in a plane normal to the former. The rollers 4'l4'l are driven by means of the bevel pinions 50-50 and of the shafts 5 I5 I by the shaft 18 actuated by the altitude pointing wheel IS, the rotation of which is, as explained above, proportional to the radial-horizontal component Vhr situated in the plane of sight. The rollers 4848' are driven by means of the pinions 52-5252 and of the shafts 5353-53 by the shaft 45 driven by the azimuth pointing wheel 32, the rotation of which provides the lateral component Vr. normal to the plane of sight.

A horizontal hand 33 moving as shown above over a dial 34 is fixed on the orientable receiving train perpendicularly to the axle 54 of the receiving rollers 2222. When the sphere is set into motion by the driving rollers 41-41 and 4848', the axle 54 of the movable train is displaced azimuthally about the shaft 49 and reaches a position of equilibrium in which the rollers 22- 22" run at the same velocity. In that position the axle 54 is evidently parallel to the axis horizontal of rotation of the sphere 46 and the hand 33 indicates the direction of movement of the target. On the other hand, the rotation ,of the rollers 2222 is transmitted by a shaft or flexible cable 55 to a tachometer 56 which indicates on an appropriate graduation the magnitude of the speed of the airplane.

A graduated dial 5'! movable in front of an index 58 is driven by the azimuth pointing wheel 32 by means of an endless screw 59, and indicates the azimuth of the sighting tube 24. The dial 34 is also driven in azimuthal rotation by the wheel 32 by means of the shafts 60, BI and of the screw 62, so that the position of the hand 33 in respect to the dial 34 shows directly the direction of movement of the airplane, i. e. the angle formed by the course of the airplane with a fixed direc tion, for instance north-south.

The apparatus heretofore described and. diagrammatically illustrated in Fig. 4 has, however, in practice, the following drawbacks:

Firstly, the continuous azimuth pointing wheel 32 which directly controls the azimuthal displacements of the sighting tube, rotates at a velocity equal to the angular azimuthal velocity of the target, which velocity is essentially variable depending on the range of the target, even when the linear speed of the airplane is constant. The continuous pointing is therefore difficult to perform with the same regularity for the different possible ranges of the target. On the contrary, the finding in direction .of the target may be rapidly performed.

On the other hand, the fact that this radialhorizontal component of the speed of the target is obtained by the following up of the horizontal range in a device which requires that the altitude SEARCH ROOM H be known, is very often obstructive as the telemeters do not always comprise means permitting to read directly the altitude H of the telemetered target.

Two difierent solutions will be hereinafter described which permit one to avoid the two above mentioned drawbacks, i. e. the necessity of knowing the altitude of the target and the irregular pointing in direction.

The first of these solution consists in materialising the triangle AuOAo of the Figure 1 not at a fixed scale, but at a variable scale of whilst keeping a constant value for the side of that materialised triangle which is represented by the screw of altitudes.

Let auoa'o (Figure 5) represent the rightangled triangle AoOA'o (Fig. 1) reduced to the scale the sides of which will have therefore the following values:

is measured from the point as along aoao, and if a perpendicular oa is drawn from the point 0 onto can, a triangle oaoa is obtained which is similar to oaoa'o and the side aoa" of which is equal to Thus a simple means is provided for constructing at any moment the triangle .oaoa'n; it suifices to dispose on a rod a'oao of constant length a movable slide on which is articulated a rod o'a." carrying at its end a" a socket in which slides the rod oao carrying the sighting tube and a pointer moving over an inverse scale of ranges having its origin at the point ao. By displacing the point 0, as in the case of point 25 of Figure 4, the pointer a" is brought in :front of the graduation of the scale corresponding to the telemetric range. In the case when the tele-altimeter is provided, one may use the altitude by providing on the slide 0' a pointer movable over a scale parallel to aua'o and having its origin in an.

However, as the length 0a fl=% depends now on the altitude, the rotation speed of the altitude pointing wheel, controlling the displacements of the point 0, becomes itself a function of the altitude; for eliminating this drawback, said altitude pointing wheel controls, according to the invention, the displacements of the point 0 by means of a change speed device controlled by the displacements of the slide 0 and reducing the rotation velocity of the wheel at the ratio of the rotation velocity of this wheel will therefore be proportional to:

i. e. to the lateral linear speed of the target which for a given path and speed of the airplane is independent of the range, so that the second drawback, explained above, of the apparatus according to Fig. 4, is thus completely eliminated.

Fig. 6 shows a form of embodiment of the apparatus comprising the improvement, the principle of which has just been explained. This apparatus comprises a fixed circular horizontal plate ll around the vertical shaft [2 of which may rotate in azimuth a frame l3 carrying the sighting tube 24, the altitude and azimuth pointing wheels I9 and 32 respectively and the combining sphere 46. An altitude screw l 5 controlled by the knob l6 by means of bevel pinions 63 journalled in the frame [3 is disposed along the axis of the plate I I, and along this endless screw is displaced without rotation a nut 28 guided by the slide l4 and provided with a pointer 28' moving over a scale graduated in On the nut 28 is articulated an arm 64 having in extension of its end a pointer 65' movable in front of a scale graduated in D0 and traversing a long guiding socket 65, the axis of which is perpendicular to the arm 64 carrying it, and in which slides the rod 23 carrying the sighting tube 24; one end of this rod 23 slides, as mentioned above, in a socket 26 articulated on a cap l4 situated at the upper end of the slide I4 guiding the nut 28 of the altitude screw I5, whilst the other end of the rod 23 is articulated on a nut 20 movable along the horizontal screw [8 journalled in the arm I! of the orientableframe l3. The screw I 8 is controlled by the wheel I 9 by means of a change speed device comprising a plate 66 and a friction roller 61 slidably keyed on the extension of the screw l8 and the eccentricity of which in respect to the centre of the plate 68 is constantly maintained equal to l H For that purpose, the knob I6 controlling the disvelocity of the nut 20 will be proportional to ro H H and the sighting tube 24 will be correctly pointed in elevation.

The nut 2|) carries by means of the member H a friction roller 12 contacting with the fixed plate II and slidably keyed on a shaft 13 journalled in the frame I3 and parallel to the horizontal screw I8. The shaft 13 is controlled by the azimuth pointing wheel 32 by means of a change speed device comprising a plate 66' and a roller 61', controlled itself, exactly as in the case of the similar device 66-61, by the altitude setting screw 15. When the azimuth pointing wheel rotates at a speed proportional to L aX h the orientable frame [3 and the sighting tube 24 which it carries rotate in azimuth in respect to the fixed plate H at an angular velocity proportional to We, so as to maintain the sighting tube 24 correctly pointed in azimuth.

The altitude pointing wheel l9 and the azimuth pointing wheel 32, rotating as indicated above, at velocities respectively proportional to Vhr and V1, respectively, drive two rollers 41, 48 (or two pairs of rollers, as shown in Figure 4) the axles of which are horizontal and which are set at right angles to each other and in contact with a great circle of the sphere 46 resting on a screw or on an orientable roller on which said sphere may freely rotate.

The receiving roller 22 mounted in the fork shaped member 2| pivoted around an axis in line with the vertical diameter 2| of the sphere, will be set, as this has been explained above, together with the hand 33 which is integral with it, to indicate the direction with respect to the sighting plane of movement of the airplane on the grad- I uated dial 34.

In order to obtain the numerical value of the speed of the target, the rotation velocity of the disc 22 or, which is the same, the resultant rotation velocity of the sphere 46, is measured. For that purpose, the sphere 46 rests by the lower end of its vertical diameter 2| on a directible roller 18 which thus forms a bearing point; this roller is integral with a bevel pinion 19 which, by means of bevel pinions [9, drives the shaft of a tachometer 80.

The second solution permitting to eliminate the aforementioned drawbacks of the apparatus according to Fig. 4, is based on the transformation of the radial-horizontal speed of the target into an angular resolved speed, the principle of which is represented in the diagrams of Figs. 7 and 8.

Let A (Fig. 7) be the actual position of the target situated at a distance OA0=D0 from the pointing apparatus, said target moving at a speed AoA=V contained in the horizontal plane P, whereas the altitude of the airplane is assumed to be constant. The speed V may be decomposed into two vectors, one of which, AOB=Vhr, situated in the plane of sight S, is

'the radial-horizontal speed, and the other, AB=VL, normal to the former and situated in the plane P, is the lateral speed of the target. The component Vhr may in turn be decomposed into two vectors, one of which, AOC=Vr, directed according to 0A0 is the radial speed, and the other, CB=Vs, normal to AoC is the sital speed.

By projecting the triangle AoAB onto the plane of sight S about the line $212, one obtains the polygon AoABC which has to be constructed for determining the value V of the speed and the orientation angle Z of the target.

The angle AOOBZIUS (Fig. 7) is the angular elevational speed, and the angle aoOa=wa (anab being the projection onto the horizontal plane containing the point 0 of the triangle AoAB) is the angular azimuthal speed of the target; these are therefore the angular components in the plane S and in the plane P of the movement of the sighting tube.

The following relations evidently exist between these various values:

So being the elevation angle and D11 the horizontal range of the target.

It is therefore seen that in order to drive the sighting tube or tubes by means of pointing wheels rotating proportionally to Vmand to VL, it will be necessary, the initial distance Do being provided by the rangefinder, to perform the following operations:

First, to transform D0 into the horizontal range Dh -Dn cos So (1) Second, to transform the lateral speed V1. into an angular azimuthal speed according to the relation Vt it E Third, to resolve the radial-horizontal velocity Var of the altitude pointing wheel into the radial velocity Vr and elevational velocity V5; (3)

Fourth, to transform the linear elevational velocity Vs into angular elevational velocity according to the relation Finally, in order that all these operations shall be continuous, it is necessary to follow up the values of the range Do and of So which are furnished to the devices permitting to obtain D11 and w. according to (1) and (4); for the following up of Do one will use the radial velocity Vr found as per (3), and for the following up of So, the angular elevational velocity 1125.

The diagrams of Figures 9 and 10 correspond to the case where the speed V=A0A of the airplane is not in a horizontal plane, but is inclined by an anglez' in respect of the horizontal plane P.

This speed V may be resolved into a vertical speed AD=BE:V1;, and into a horizontal speed AOD=Vh, and the problem consists in determining, in magnitude and in direction, the horizontal speed Vh, whereas the vertical speed Vv may be either estimated at sight or measured in any known way, for instance by means of an altitudegraph.

The horizontal speed Vn may be resolved as in the previous case, into a radial-horizontal speed Vhr=AOE and a lateral speed V1. may be determined as above from the horizontal distance SEARCH RGOIW Dh and from the angular velocity of pointing in azimuth we.

In order to take into consideration the inclination 2' of the course of the airplane, the radialhorizontal speed is resolved into three vectors: EB, which is the vertical speed Vv of the target, BC, which is the elevational speed V5, and A00, which is the radial speed Vr.

Figure 10, in which the triangle AoED has been turned about the axis .r'a: onto the plane of sight 8, permits one to understand more easily the principle according to which the apparatus will be constructed. It is seen from this figure that, if no account were taken of the inclination of the speed. of the target, the radial-horizontal speed AOE=Vhr would be resolved according to Figure 8 into an elevational speed EF=V1S and into a radial In order to take into account the variation of altitude, the vertical speed EB=V is resolved into two vectors respectively parallel to AoF and EF, and thus are obtained the elevational and radial components Vzs=EG and V2r=FC', which, by being added to or subtracted from V15 and Vlr, give the true values VS=BC and VT=AoC of the elevational and radial speeds of the target. It is, therefore, clear that in order to take into account the variation in altitude of the target, it is simply necessary to provide the apparatus with a device for resolving the vertical speed vector into its sital and radial components.

Such an apparatus is represented in Figure 11.

This apparatus comprises a sphere device similar to those of Figs. 4 and 6 and comprising the sphere 8|, the two driving rollers 81, 88 rotating at speeds proportional to the components vhr and VI. of the speed V of the airplane and the receiv ing roller 82 with its index 83 on the gradation 84. The driving rollers 81, 88 are actuated directly by the wheels 9| for elevation pointing and 92 for azimuth and control the sighting tube connected thereto by shafts 89, 90.

The shaft 90 controlled by the azimuth pointing wheel 92 drives on the other hand the roller 93 adapted to slide along said shaft, and driving by friction a plate 94, the rotation of which is transmitted by the bevel pinion 95, the shaft I63, the endless screw 96 and the tangential wheel 97 to the sighting tube I25. The roller 93 is constantly maintained at a distance from the centre of the plate 94 which is proportional to the horizontal range Dh of the target by means of a device constituted by a rotating plate 99 on which is journalled a screw I00, on which is engaged a nut IOI carrying a finger I02 engaged in two slides I03, I04 set at right angles. By means of devices which will be hereinafter described, the finger I02 is constantly maintained at a distance from the centre of the plate 99 which is proportional to the telemetric range Do, and the screw is pointed in elevation by the rotation of said plate, so that the distances of the axes of the slides I03, I04 from the centre of the plate are proportional to the horizontal range Dh and to the altitude H0 of the target respectively. The altitude H0 is shown on a scale I by a pointer integral with the slide I 04, whereas the slide I03 controls the displacements of the roller 93.

When the sighting tube I25 follows the target in a continuous manner, the plate 94 rotates at a velocity proportional to 7.0a, so that the roller 93 and consequently the shaft 90, the wheel 92 and the driving roller 88 of the sphere 8| rotate at a velocity proportional to weDn=VL, which is the desired result.

A differential I06, the satellite drum of which is driven by the wheel I01, is arranged between the plate 94 of the change speed device described above, and the sighting tube I25, said differential permitting a rapid azimuthal resetting of the sighting tube to be performed.

The wheel for continuous elevation pointing, 9i, drives by means of a shaft 89' the driving roller I08 of a resolving sphere I09, said roller I08 being adapted to be oriented in a manner to form with the plane of one of the receiving rollers II 0 or I II an angle equal to the angle of ele- Vational. If it is supposed that this roller is oriented according to the initial angle of elevation So and that it is driven by the wheel 9! at a velocity proportional to the radial-horizontal speed Vhr of the airplane, it will be seen that the roller I I0 will rotate at a velocity proportional to the radial speed Vr=Vhr cos S0, and the roller I I I at a velocity proportional to the elevational speed Vs=Vnr sin So of the target. The rotation of the roller H0 is used, on one hand, for following up the range Do in the device providing the horizontal range D11 and, for this purpose, said roller '0 controls, by means of a shaft H2 and the pinions H4, H4, a shaft II5 which drives in rotation, by means of the bevel pinions H6, the range setting screw I00, causing thus the displacement along this screw of the nut IOI controlling the slides I03, I04; the rotation of the roller I I0 is used, secondly, for controlling, by means of pinion H4 and shafts II! and H8, an endless screw II9 driving a nut I20 which controls the eccentricity of a roller IZI' of a change speed device comprising a plate I22, said roller I2! being driven in rotation by the roller III of the resolving sphere I09 and the plate I22 being connected by means of a shaft N3, the endless screw I23 and the toothed wheel I24 with the sighting tube I'25.

When the sighting tube follows the target in elevation it moves at an angular velocity of we; the plate I22 rotates, therefore, at a velocity proportional to W5 and, as the roller I2I is maintained at a distance proportional to Do from the centre of that plate I22, it rotates at a velocity proportional to Vs=wsDO, and this is also the case for the roller I'II. It is, therefore, seen that when the wheel 9| is driven in a manner to follow the target, it actually rotates at a velocity proportional to the radial-horizontal speed Vhr of the target.

The shaft II 3 of the plate I22 carries, moreover, an endless screw I26, driving the plate 99, this resulting in the continuous resetting of the site of the range screw I00; said shaft carries an endless screw I28 meshing with a toothed wheel I29 which permits the continuous resetting of the orientation in site of the driving roller I08 of the decomposing sphere I09.

Similarly, the quick resetting of elevational of the range screw I00, of the roller I08 of the revolving sphere andof the sighting tube I25 is performed by means of a wheel I'32 controlling the drum of satellites of a differential I33 mounted on the shaft 3 of the plate, I22.

These rapid resetting wheels of range and of elevation I30 and I32, control their respective differentials by means of appropriate nonreversible transmissions which are not .represented on the drawing (for instance by means of endless screws and tangential wheels), so as not to react upon one another.

In order to introduce the vertical speed vector DA=Vv, the apparatus comprises a motor of con- 11 stant speed I42 controlling a shaft I43 on which is keyed the plate I44 of a change speed device, the roller I45 of which is maintained at a distance proportional to the vertical speed Vv from the centre of the plate I44, this roller being controlled by a knob I46 by means of an endless screw I45 and a nut I45", the rotation of this screw being transmitted to a shaft I54 provided with a threading I54 on which is engaged a nut I53 provided with an index I14 movable in front 10 of a scale of vertical speed I15. This roller itself rotates therefore at'a velocity proportional to Vv, and drives by means of its shaft a decomposing device I"I09'IIOIII', which is exactly similar to the device I'08--I08I I0I II heretofore described, and 'the driving roller I08 of which is oriented in site, as the roller I08, by the shaft II3 of the change speed device l2I-l22, by means of the endless screw I28 and of the toothed wheel I. 20

The components V2s and V2: provided thus by the rollers I I0, H I, are combined with the components vls and Vlr provided by the rollers IIll,

III by means of the adding differentials I48 and I49 mounted on the shafts of the rollers I I0 and 5 I I I, and the drums of satellites of which are controlled by the rollers I I0 and III.

The composing sphere 8i provides, finally, the value and the direction of the horizontal component V11 of the movement of the target. In order to reconstruct the speed vector V, a device is provided which comprises a rod I50 articulated by one of its ends on a nut I5I engaged on a threaded portion I52 of a shaft I52 controlled by the tachometer 86; the other end of the rod I'50 rests freely on the nut I 53 (or slides in a socket articulated on that nut) which is engaged, as heretofore explained, on the threaded portion I54 of the shaft I54 controlled by the radial displacements of the nut I45. It is, therefore, clear that the length of the rod I comprised between the nuts I5II53 gives the length of V, whereas the angle formed by that rod with the shaft I52, angle shown on the graduated sector I55, gives the inclination i.

The wind-correction is performed according to this invention by resolving the speed of the wind into two vectors, one situated in the plane of sight and the other in a vertical plane normal to the plane of sight, and by adding these two com- 50 ponents respectively to the radial-horizontal speed Vm and to the lateral speed VL, controlling the recomposing sphere 8|. For that purpose. the shaft I43 driven'by the constant velocity motor I42 controls the plate I56 of a change 55 speed device, the roller I 51 of which is constantly maintained at a distance from the centre of the plate I56 which is proportional to the speed w of the wind. This roller I56 controls the driving roller I58 of a decomposing sphere I59, the re- 60 ceiving rollers I 60, SI of which rotate, therefore, at the velocities W! and W1, and control the drums of satellites of the adding differentials I62,

I63 mounted on the shafts 80 and 90 of the rollers 81 and 8& of the sphere 8|, respectively. The 65 roller I51 is controlled in radial displacement by a nut I'64 carrying a pointer movable in front of the speed scale I65, said nut being engaged on a screw I66 controlled by hand by means of the knob I61. 70

The driving roller I50 of the sphere I50 is oriented to form with the plane of the roller I60 the angle y which is formed by the direction of the wind with the plane of sight; this orientation of the roller is continuously reset by the azi- 12 muthal displacements of the sighting tube by means of the shafts I68, I69, of the endless screw I10 and of the toothed wheel I1I, whereas the initial setting of the angle y is performed by the handle I12 controlling the drum of the differential I13.

Inorder to facilitate this operation of windcorrection, these angles are counted from the direction north-south by driving in azimuth the graduation 84 in front of which moves the index hand 83 of the recomposing sphere 7,8I. This graduation 84 gives therefore directly and at every moment'the direction yr of the plane of sight and the angle g2 formed by the course of the airplane with the direction north-south.

A device similar to the one described above for the wind correction may be provided for performing the correction of the displacements of the shooter.

I claim:

1. Auxiliary sighting apparatus for ascertaining the velocity and direction of movement of an aerial target, comprisin in combination a sighting tube, two wheels for controlling, respectively, the displacements in elevation and in azimuth of said sighting tube, altitude setting means, a device actuated by said elevation control wheel and said altitude setting means for determining the horizontal range of the target, a device actuated by the azimuth pointing wheel for multiplying said horizontal range by the angular azimuthal displacement of said sighting tube, a sphere, a supporting member on which said sphere is adapted to rotate freely, two driving rollers contacting with a horizontal great circle of said sphere and set at from each other, means for actuating one of said driving rollers by the elevation-controlling wheel, means for driving the other roller by a part of the said multiplying device, and an orientable receiving roller driven by said sphere.

2, Auxiliary sighting apparatus for ascertaining the velocity and direction of movement of an aerial target, comprising in combination, a frame adapted to rotate in azimuth, a vertical screw journalled in said frame, a nut adapted to move along said screw without rotating, a scale of altitudes parallel to said screw, an index hand carried by said nut and moving in front of said scale, a socket articulated on said nut, a horizontal screw journalled in said frame, a nut adapted to move along said horizontal screw without rotating, a sighting tube, a rod integral with said sighting tube, having one end articulated on said nut, movable along said horizontal screw and the other end sliding freely in said socket articulated on said nut movable on said vertical screw, an altitude-pointing wheel, means for rotating said horizontal screw by said altitude-pointing wheel, an azimuth-pointing wheel controlling the azimuthal rotation of said frame, a sphere, a supporting member on which said sphere may freely rotate, two driving rollers contacting with a horizontal great circle of said sphere and set at 90 from each other, means for directly transmitting to one of said driving rollers the rotation of said horizontal screw, means for transmitting to the second driving roller the rotation of said azimuthpointing-wheel, said means comprising a change speed device constituted by a circular plate, a shaft perpendicular to said two screws journalled in said frame, said circular plate being adapted to rotate on said shaft, and a friction-roller adapted to be displaced in unison with said nut movable along said horizontal screw; an orientable receiving train, constituted by a fork shaped mem- SURW ROW her pivoted about the vertical axis of said sphere and a roller mounted in said fork shaped member eccentrically in respect to the vertical axis of the sphere with which it contacts; a graduated dial, means for transmitting the rotation of said azimuth-pointing wheel to said dial, an index hand carried by said receiving train and moving over said dial, and a tachometer for measuring the resultant velocity of rotation of said sphere.

3. Auxiliary sighting apparatus for ascertaining the velocity and direction of movement of an aerial target, comprising in combination a sighting tube, an altitude-pointing wheel, an azimuthpointing wheel, means for transmitting rotation to said sighting tube from said pointin wheels during sighting at velocities proportional to the elevation and azimuth velocities, respectively, of the target; a sphere, a supporting member on which said sphere is adapted to rotate freely, two driving rollers contacting with a horizontal great circle of said sphere and set at 90 from each other, means for transmitting rotation to said driving rollers from said pointing wheels at velocities proportional to the radial-horizontal and lateral components, respectively, of the target movement, and an orientable receiving roller driven by said sphere.

4. Auxiliary sighting apparatus for ascertaining the velocity and direction of movement of an aerial target, comprising, in combination, a sighting tube, two Wheels controlling the displacements in altitude and in azimuth, respectively, of said sighting tube, a sphere, a supporting member on which said sphere may rotate freely, two driving rollers contacting with a horizontal great circle of said sphere and set at 90 in respect to each other, means actuated by said altitudeand azimuth-pointing wheels for driving said driving rollers at velocities proportional, respectively, to the radial-horizontal and lateral components of the speed of the target, an orientable receiving train comprising a fork-shaped member pivoted about the vertical axis of said sphere and a roller mounted in said fork-shaped member eccentrically in respect of the vertical axis of the sphere with which it contacts, a graduated dial, an index hand coacting with said receiving train and moving over the said dial, and a tachometer device for measurin the resultant velocity of rotation of said sphere.

5. Auxiliary sighting apparatus for ascertaining the velocity and direction of movement of an aerial target, comprising, in combination, a sighting tube, an altitude pointing wheel, an azimuth pointing wheel, transmission devices provided between said sighting tube and said pointing Wheels adapted to transmit to the sighting tube the an ular elevation and azimuth velocities of the target while the wheels are rotated at velocities proportional to the linear radial-horizontal and lateral components, respectively, of the movement of the target; a sphere, a supporting member on which said sphere is adapted to rotate freely, two driving rollers contactin a horizontal great circle of the sphere, set at from each other, means for actuating one of said rollers by the altitude pointing wheel, means for actuating the other roller by the azimuth pointing wheel, and an orientable roller driven by said sphere.

AUGUSTE LOUIS RICORDEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,256,234 Innes Feb. 12, 1918 1,663,211 McNab Mar. 20, 1928 1,701,582 Mengden Feb. 12, 1929 1,757,597 Smith May 6, 1930 FOREIGN PATENTS Number Country Date 712,016 France July 8, 1931 

